When the Indian River Lagoon on Florida’s Atlantic coast became much saltier after 2011, Arnoldo Valle-Levinson began to investigate.

The UF professor of civil and coastal engineering sciences in the College of Engineering checked local tidal gauges, revealing that seas in the region were rising nearly 10 times faster than the long-term rate recorded in that region. When he reviewed tidal data for the entire eastern seaboard, he found similar numbers for all the tide gauge stations south of Cape Hatteras, revealing the regional extent of the "hot spot."

Sea level rise hot spots — bursts of accelerated sea rise that last three to five years — happen along the U.S. East Coast thanks to a one-two punch from naturally occurring climate variations, according to a new study lead by Valle-Levinson.

After UF scientists identified the hot spot reaching from Cape Hatteras to Miami, they probed the causes by analyzing tidal and climate data for the U.S. eastern seaboard. The study, published online today in Geophysical Research Letters, shows that seas rose in the southeastern U.S. between 2011 and 2015 by more than six times the global average sea level rise that is already happening due to human-induced global warming.

The study’s findings suggest that future sea level rise resulting from global warming will also have these hot spot periods superimposed on top of steadily rising seas, said study co-author Andrea Dutton, assistant professor in UF’s department of geological sciences in the College of Liberal Arts and Sciences.

“The important point here is that smooth projections of sea level rise do not capture this variability, so adverse effects of sea level rise may occur before they are predicted to happen,” Dutton said. “The entire U.S. Atlantic coastline is vulnerable to these hot spots that may amplify the severity of coastal flooding.”